Quick-acting coupling

ABSTRACT

A first coupling (51) and a second coupling (52) composing a quick-acting coupling (26) are respectively provided with check valve bodies (54)(154) and non-spill valve bodies (55)(155). When both the couplings (51)(52) are manipulated for the disconnection thereof, a leak of liquid is adapted to be prevented by means of the respective check valve bodies (54)(154) as well as a spill of liquid is adapted to be prevented by means of the non-spill valve bodies (55)(155). The respective non-spill valve bodies (55)(155) are fitted slidably inside respective non-spill valve port surfaces (71)(171) so as to carry out a liquid sealing respectively. Further, at the time of disconnecting manipulation of the coupling (26), a volume of the liquid phase portion within a non-spill valve casing chamber (63) is adapted to be increased by the movement of a non-spill valve casing (56) in which the first non-spill valve body (55) is fitted.

This application is a division of application Ser. No. 07/423,276 filedOct. 18, 1989.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a quick-acting coupling which isemployed for quickly connecting or disconnecting halfway portions of ahydraulic line, for example for use in a hydraulic clamp apparatus forfixing a work in a machine tool.

2. Description of the Prior Art

A quick-acting coupling as a subject of the present invention will beexplained more concretely hereinafter. The quick-acting coupling is ofthe type comprising a pair of couplings provided with check valves andnon-spill valves (in other words, spill preventive valves) respectivelyso that a leak of liquid such as a working oil can be prevented by meansof the check valves and a spill of liquid can be prevented by means ofthe non-spill valves when the couplings are disconnected.

Such a quick-acting coupling with the check valves and the non-spillvalves on opposite sides for use in liquid is used for preventingproducts and atmosphere from being contaminated by the liquid becausethe coupling is adapted to prevent the spill-out of liquid outside theconnection ports during the disconnecting manipulation thereof. Itsbasic construction known by the inventor of the present invention isshown in FIG. 11 for a first conventional embodiment.

In FIG. 11(a), a quick-acting coupling 26' includes a first coupling 51'and a second coupling 52'.

The first coupling 51' is provided with a coupling body 53', a checkvalve body 54', a non-spill valve body 55',a non-spill valve casing 56',a check valve spring 57'. non-spill valve casing spring 58' and a rod59'.

The coupling body 53' is provided in its inside with a non-spill valvecasing chamber 63' and a check valve chamber 66' in order from the buttconnection side JA to the pull-off disconnection side UA. The checkvalve chamber 66' accommodates the check valve body 54' and the checkvalve spring 57' therewithin. The non-spill valve casing chamber 63'accommodates the non-spill valve casing 56' therewithin. The non-spillvalve body 55' is disposed so as to face the non-spill valve portsurface 71' at the leading end of the casing bore 56a' of the non-spillvalve casing 56'. The inside of the non-spill valve port surface 71' isin communication to the check valve chamber 66' through the casing bore56a' of the non-spill valve casing 56', and the non-spill valve body 55'and the check valve body 54' are connected to each other through the rod59'.

The check valve body 54' is urged toward the butt connection side JA bymeans of the check valve spring 57' within the check valve chamber 66'so as to be brought into contact with a check valve seat 72' of thecheck valve chamber 66' for the valve closing. On one hand, the rod 59'transmits the movement of the non-spill valve body 55' toward thepull-off disconnection side UA by an external force to the check valvebody 54' so as to shift the check valve body 54' to its valve openingposition and on the other hand, it limits the movement of the non-spillvalve body 55' toward the butt connection side JA. The non-spill valvecasing 56' is adapted to be pushed toward the butt connection side JA bymeans of the non-spill valve casing spring 58' within the non-spillvalve casing chamber 63' so as to bring the non-spill valve port surface71' into contact with the non-spill valve body 55' for the valveclosing.

The second coupling 52' is provided with a coupling body 153', a checkvalve body 154', a non-spill valve body 155', a check valve spring 157',a non-spill valve spring 158' and a rod 159'.

The coupling body 153' is provided in its inside with a non-spill valvechamber 163' and a check valve chamber 166' in order from a buttconnection side JB to a pull-off disconnection side UB, and thenon-spill valve chamber 163' is in communication with the check valvechamber 166'. The check valve chamber 166' accommodates the check valvebody 154' and the check valve spring 157' therewithin, the non-spillvalve chamber 163' accommodates the non-spill valve body 155'therewithin, the non-spill valve body 155' is disposed so as to face anon-spill valve port surface 171' at the leading end of the non-spillvalve chamber 163', and the rod 159' is interposed between the non-spillvalve body 155' and the check valve body 154'.

The check valve body 154' is urged toward the butt connection side JB bymeans of the check valve spring 157' within the check valve chamber 166'so as to be brought into contact with a check valve seat 172' of thecheck valve chamber 166' for the valve closing. The rod 159' transmitsthe movement of the non-spill valve body 155' toward the pull-offdisconnection side UB by an external force to the check valve body 154'so as to shift the check valve body 154' to its valve opening position.On the one hand, the non-spill valve body 155' is adapted to be pushedtoward the butt connection side JB by means of the non-spill valvespring 158' within the non-spill valve chamber 163' so as to close thenon-spill valve port surface 171' of the non-spill valve chamber 163'and on the other hand, it is adapted to be pushed toward the pull-offdisconnection side UB by an external force so as to open the non-spillvalve port surface 171'.

In the above-mentioned basic construction, a conventional constructionfor liquid-tightly sealing the non-spill valve casing chamber 63' andthe non-spill valve chamber 163' under the disconnected condition ofboth the couplings 51', 52' will be explained more in detailhereinafter.

In this prior art, the non-spill valve bodies 55', 155' are of a seatvalve type. The first non-spill valve body 55' is adapted to be broughtinto contact with the tapered non-spill valve port surface 71' from thebutt connection side JA to the pull-off disconnection side UA for thevalve closing and the second non-spill valve body 155' is adapted to bebrought into contact with the tapered non-spill valve port surface 171'from the pull-off disconnection side UB to the butt connection side JBfor the valve closing.

The quick-acting coupling 26' for use in liquid having theaforementioned construction operates as follows during the connectingmanipulation.

FIG. 11(a) shows the connection starting condition. The respective valvebodies 54', 55', 154', 155' are shifted to the valve closing positionsby the springs 57', 58', 157', 158' respectively so as to shut off thecommunication between both oil supply and discharge ports 62', 162' atthe opposite ends. Under this condition, the non-spill valve casing 56'of the first coupling 51' and a valve casing pushing portion 156' of thesecond coupling 52' are brought into contact with a sealing means 84'for sealing off.

When the first coupling 51' is advanced toward the butt connection sideJA on the right side with respect to the second coupling 52', thecondition shown in FIG. 11(b) is obtained after the followingoperations. Firstly, the non-spill valve casing spring 58' is contractedso that the non-spill valve body 55' is separated apart from thenon-spill valve port surface 71' and both the valve bodies 55', 155' arebutted to each other. Then, the non-spill valve spring 158 is contractedso that the non-spill valve body 155' is separated apart from thenon-spill valve port surface 171' and the rod 159' is brought intocontact with the check valve body 154'.

Further, as the first coupling 51' is advanced, as shown in FIG. 11(c),firstly the first check valve body 54' is shifted to its valve openingposition and then as shown in FIG. 11(d), the second check valve body154' is shifted to its valve opening position so that both the oilsupply and discharge ports 62', 162' are communicated to each other.

On the other hand, the following operations of the quick-acting coupling26' are carried out during the disconnecting manipulation subsequent tothe connection completed condition shown in FIG. 11(d).

When the first coupling 51' is retreated toward the pull-offdisconnection side UA on the left side with respect to the secondcoupling 52', as shown in FIG. 11(c), firstly the second check valvebody 154' is shifted to its valve closing position and then as shown inFIG. 11(b), the first check valve body 54' is shifted to its valveclosing position. As the first coupling 51' is retreated, the followingoperations are carried out. That is, as the non-spill valve spring 158'and the non-spill valve casing spring 58' extend, firstly the second rod159' is separated apart from the check valve body 154' and the secondnon-spill valve body 155' is brought into contact with the non-spillvalve port surface 171' for the valve closing and then the firstnon-spill valve port surface 71' is brought into contact with thenon-spill valve body 55' for the valve closing.

There are, however, following problems associated with theabove-mentioned first conventional embodiment.

(a) A spill-out of liquid is caused during the disconnectingmanipulation.

Since the quick-acting coupling 26' operates as mentioned above, a timelag can't help being brought about in the valve closing timing of thenon-spill valve bodies 55', 155' at the time of disconnectingmanipulation of both the couplings 51', 52'.

Further, at the time of connecting manipulation of both the couplings51', 52', since firstly it is necessary to seal between the non-spillvalve casing 56' and the valve casing pushing portion 156' by means ofthe sealing means 84', a gap can't help being provided between both thebutting surfaces of the non-spill valve bodies 55', 155' in order tocompensate contact errors between the respective non-spill valve bodies55', 155' and the respective non-spill valve port surfaces 71', 171'. Inother words, just before disconnecting both the couplings 51', 52', agap is provided between both the butting surfaces of the non-spill valvebodies 55', 155'.

Since there is a time lag in the valve closing timing and there isprovided a gap between both the valve bodies in that way, a liquid poolis formed between both the non-spill valve bodies 55', 155' just beforetheir disconnections. Further, the quantity of this liquid pool can'thelp become larger owing to a gap provided by chamfers formed at theperipheral portions of both the valve bodies 55', 155'. Resultantly, thespill-out of liquid is caused at the time of disconnecting manipulation.

(b) The durability for the spill prevention is low.

Since the non-spill valve bodies 55', 155' of the seat valve type andthe non-spill valve port surfaces 71', 171' are apt to be damaged byforeign substances and the like bitten therebetween, the liquid-tightsealing is readily broken. Therefore, the durability for the spillprevention is low.

(c) A large force is required for the connecting manipulation.

Since the non-spill valve bodies 55', 155' are shifted to the valveclosing positions with the non-spill valve casing chamber 63' and thenon-spill valve chamber 163' being kept under high pressure conditionsat the time of disconnecting manipulation of both the couplings 51',52', a large manipulation force is required for the connectingmanipulation at the next time.

Further, has been known another quick-acting coupling having a differentbasic construction from the above-mentioned first conventionalembodiment and provided with a cleaning device of a fluid blow type.This coupling is adapted to remove foreign substances attached toconnecting portions of a pair of couplings of a quick-acting coupling bymeans of the blow employing a cleaning fluid such as a pressure air andthe like so as to clean the connecting portions when the pair ofcouplings is connected.

As such a quick-acting coupling with the cleaning device, has been knownthe one disclosed in Japanese Provisional Utility Model No. 1985-52496(referred to as a second conventional embodiment, hereinafter)previously proposed by the inventer of the present invention. Thiscoupling is constructed as follows, as shown in FIG. 12.

A connecting insert portion 161" is formed at the leading end portion ofa coupling body 153" of a second coupling 52". A flow passage 160" on asecond coupling side is opened in the leading end surface 161a" of theconnecting insert portion 161", and an annular sealing contact portion189" is formed in the connecting insert portion 161" at the centralportion in the right and left direction of an outer surrounding surface161b" thereof 161".

A connecting receive mouth 61" is formed in the leading end portion of acoupling body 53" of a first coupling 51" in a concaved fashion. A flowpassage 60" on a first coupling side is opened in the inmost end surface61a" of the connecting receive mouth 61", and an annular sealing contactportion 89" is provided in the connecting receive mouth 61" at thecentral portion in the right and left direction of an inner surroundingsurface 61b" thereof 61". A plurality of ejection holes 85" are openedin the inner surrounding surface 61b" of the connecting receive mouth61" at the leading end portion in a forward inclined manner so as toeject a cleaning fluid F. Under the midway condition of the connectionbetween the first coupling 51" and the second coupling 52" as shown inFIG. 12(a), the cleaning fluid F ejected from the ejection holes 85" issprayed to both the leading end surface 161a" and the outer surroundingsurface 161b" of the insert portion 161" to clean these portions.

Under the connected condition between the first coupling 51" and thesecond coupling 52" as shown in FIG. 12(b), both the sealing contactportions 89", 189" are brought into contact with each other so as toseal between both the connection surfaces of the connecting receivemouth 61" and of the connecting insert portion 161".

Further, the aforementioned second conventional embodiment is alsoprovided with ejection holes 85a" opened in the inner surroundingsurface 61b" of the receive mouth 61" at the inmost portion as a variantof the ejection hole 85" for ejecting the cleaning fluid F as shown bythe alternate long and two short dashes line in FIG. 12(a).

There are, however, the following problems (1) and (2) associated withthe second conventional embodiment in addition to such a problem that aspill quantity of liquid from the first coupling 51" is large at thetime of disconnection between both the couplings 51", 52" because alarge liquid pool is provided in the inmost portion of the connectingreceive mouth 61" behind the sealing contact portion 89" when both thecouplings 51", 52" are disconnected.

(1) In the case of the ejection hole 85" (refer to the one shown by thesolid line in FIG. 12(a) ):

At the time of disconnecting manipulation of the quick-acting coupling26", foreign substances attached to both the leading end surface 161a"and the outer surrounding surface 161b" of the connecting insert portion161" of the second coupling 52" can be preferably removed therefrom161a", 161b" by spraying the cleaning fluid F thereto 161a", 161b".

But, is impossible to spray the cleaning fluid F to the innersurrounding surface 61b" and to the inmost end surface 61a" of the firstcoupling 51". Therefore, the foreign substances attached thereto 61a",61b" are bitten between both the connecting surfaces of the sealingcontact portion 89", 189" to cause damages thereof and/or enter the flowpassage 60" on the first coupling side or the flow passage 160" on thesecond coupling side.

(2) In the case of the ejection hole 85a"(refer to the one shown by thealternate long and two short dashes line in FIG. 12(a) ):

In this case, though it is possible to make the cleaning fluid F passthrough the connecting receive mouth 61", it is impossible to spray thefluid F to the inmost end surface 61a" and it is also impossible tospray the fluid F strongly to the inner surrounding surface 61b".

Further, when the connecting insert portion 161" is started to fit intothe connecting receive mouth 61", since the receive mouth 61" is closedand subsequently the flowing of the cleaning fluid F is stopped, itbecomes impossible to clean the outer surrounding surface 161b" of theconnecting insert portion 161".

SUMMARY OF THE INVENTION

The first object of the present invention is to prevent a spill ofliquid at the time of disconnecting manipulation of a quick-actingcoupling, to enhance the durability for such a spill prevention and toenable to make the connecting manipulation force small.

The second object of the present invention is to prevent foreignsubstances from being bitten between sealing contact portions and fromentering flow passages at the time of connecting manipulation of thequick-acting coupling.

For accomplishing the above first object, the partial construction forliquid-tightly sealing the non-spill valve casing chamber and thenon-spill valve chamber under the disconnected conditions of both thecouplings in the basic construction of the above-mentioned firstconventional embodiment is improved as follows, for example as shown inFIGS. 4 through 7.

The respective non-spill valve port surfaces (71), (171) are formed likethe casing bore inside circumferential surfaces. The respectivenon-spill valve bodies (55), (155) are fitted slidably inside thenon-spill valve port surfaces (71), (171) configurating with the casingbore inside circumferential surfaces so as to liquid-tightly seal thecasing bore (56a) of the non-spill valve casing chamber (63) and thenon-spill valve chamber (163).

Both the front side spaces and the back side spaces of the respectivenon-spill valve bodies (55), (155) are connected to each other throughconnection passages (75), (175) having small cross-sectional areas underthe valve closed conditions of the respective non-spill valve bodies(55), (155). During the disconnecting transitive stage wherein the firstcoupling (51) and the second coupling (52) are changed over from theirbutted connected condition to their pulled-off disconnected condition,the total operation lift (L) of the non-spill valve casing (56) providedby means of the non-spill valve casing spring (58) toward the buttconnection side (JA) is set larger by the value corresponding to asucking back lift (N) than an all valve closing minimum lift (M) of thenon-spill valve casing (56) required in minimum for completing the valveclosings of all the check valve bodies (54), (154) and the non-spillvalve bodies (55), (155).

In the aforementioned construction, the casing bore insidecircumferential surfaces of the non-spill valve port surfaces (71),(171) may be formed in a circular or polygonal configuration.

Further, the connection passages (75), (175) may be formed by gapsprovided by the fitting of the respective non-spill valve port surfaces(71), (171) and the respective spill preventive valve bodies (55), (155)or by connection ports passing through the respective non-spill valvebodies (55), (155).

Further more, the check valve body (54), the rod (59) and the non-spillvalve body (55) in the first coupling (51) may be formed in threemanners, namely separately, integratedly with the adjacent ones to eachother and wholly as one piece.

Similarly, the check valve body (154), the rod (159) and the non-spillvalve body (155) in the second coupling (52) may be formed in threemanners, namely separately, integratedly with the adjacent ones to eachother and wholly as one piece. In the case of the integration of thecheck valve body (154) and the rod (159), the non-spill valve spring(158) may be omitted by substituting the check valve spring (157) forthe non-spill valve spring (158).

Incidentally, as the external force for the connecting manipulation ofboth the couplings (51), (52), the operation force of an actuator suchas a pneumatic cylinder and the like or a man power of a worker may beused.

The invention functions as follow, for example as shown in FIG. 7.

The quick-acting coupling (26) operates as follows at the time ofconnecting manipulation. During the duration from the disconnectedcondition shown in FIG. 7(a) to the connection starting condition shownin FIG. 7(c) via the inserting condition shown in FIG. 7(b), therespective valve bodies (54), (55), (154), (155) are kept in the valveclosed conditions. Subsequently, during the duration for changing overto the connected condition shown in FIG. 7(f) via the connectiontransitive conditions shown in FIGS. 7(d) and 7(e), the respective valvebodies (54), (55), (154), (155) are shifted to the valve open positionsso as to communicate both the liquid supply and discharge ports (62),(162) to each other.

On one hand, the coupling (26) operates as follows at the time ofdisconnecting manipulation. During the duration from the connectedcondition shown in FIG. 7(f) to the condition shown in FIG. 7(d) via thecondition shown in FIG. 7(e), the check valve bodies (54), (154) areshifted to the valve closed positions so that the non-spill valve casingchamber (63) and the non-spill valve chamber (163) are shut out from theliquid supply and discharge ports (62), (162). During the duration fromthe condition shown in FIG. 7(d) to the condition shown in FIG. 7(c), asthe non-spill valve casing (56) is advanced toward the butt connectionside (JA) by the sucking back lift (N) with respect to the coupling body(53), the liquid phase volume within the non-spill valve casing chamber(63) is increased so as to lower the pressures within the casing bore(56a) of the non-spill valve casing (56) and the non-spill valve chamber(163) communicating to each other to a pressure level near a negativepressure. Therefore, the liquid pooled in the gap between both thenon-spill valve bodies (55), (155) butting to each other and the insidecircumferential space of the sealing means (84) is sucked backed intothe casing bore (56a) of the non-spill valve casing (56) and thenon-spill valve chamber (163) by means of the effect of the atmosphericpressure so as to liquid-tightly seal both the chambers (63), (163)under this condition. Accordingly, none of liquid leaks during thedisconnecting manipulation from the condition shown in FIG. 7(c) to thecondition shown in FIG. 7(b).

Since it becomes possible to liquid-tightly seal the non-spill valvecasing chamber (63) and the non-spill valve chamber (163) by merelyfitting the non-spill valve bodies (55), (155) inside the non-spillvalve port surfaces (71), (171), the valve bodies (55), (155) and theport surfaces (71), (171) are not damaged by the biting of foreignsubstances differently from the conventional seat valve type one so thatthe durability for the spill prevention can be enhanced.

Further, since the pressure within the non-spill valve casing chamber(63) and the non-spill valve chamber (163) are lowered nearly to theatmospheric pressure at the time of disconnecting manipulation of boththe couplings (51), (52), the manipulation force required for the nextconnecting manipulation can be made smaller.

Incidentally, in the case that the non-spill valve body (155) and therod (159) of the second coupling (52) are formed separately from thecheck valve body (154) as illustrated, the spill preventive effect maybe further improved. That is, during the duration from the conditionshown in FIG. 7(d) to the condition shown in FIG. 7(c), as the non-spillvalve body (155) and the rod (159) are advanced toward the buttconnection side (JB) by the lift (S) with respect to the coupling body(153), the liquid phase volume within the non-spill valve chamber (163)is increased so that the pressures within the casing bore (56a) of thenon-spill valve casing (56) and the non-spill valve chamber (163)communicating to each other can be further lowered.

Since the present invention is constructed and functions as mentionedabove, the following advantages can be provided.

(a) A leak of liquid can be prevented at the time of disconnectingmanipulation.

By lowering the pressures within the casing bore of the non-spill valvecasing and the non-spill valve chamber communicating to each other to apressure level near to a negative pressure as the non-spill valve casingadvances to the butt connection side by the sucking back lift withrespect to the first coupling body at the end of the disconnectingmanipulation of both the couplings, the liquid pooled within the gapbetween both the non-spill valve bodies butting each other and withinthe inside circumferential space of the sealing means is sucked backinto the non-spill valve casing chamber and the non-spill valve chamberso as to liquid-tightly seal both the chambers under this condition.Therefore, a leak of working oil can be prevented completely.

(b) The durability for the spill prevention is high.

Since the non-spill valve casing chamber and the non-spill valve chamberare liquid-tightly sealed by the fitting between the non-spill valvebodies and the non-spill valve port surfaces, they don't suffer fromdamages which might be caused by the bitings of foreign substancestherebetween. Therefore, the durability for the spill prevention can beenhanced.

(c) A small force can be enough for the connecting manipulation.

Since the pressures within the non-spill valve casing chamber and withinthe non-spill valve chamber are lowered nearly to the atmosphericpressure at the time of disconnecting manipulation of both thecouplings, a small force is required for the connecting manipulation atthe next time.

For accomplishing the above second object of the present invention, thepartial portion for blowing off the foreign substances by means of thecleaning fluid is improved as follows, for example as shown in FIGS. 4through 7.

A sealing contact portion (89) of the first coupling (51) is disposed inan inmost end surface (61a) of a connecting receive mouth (61), and asealing contact portion (189) of the second coupling (52) is disposed ina leading end surface (161a) of a connecting insert portion (161). Anejection hole (85) for the cleaning fluid (F) is opened in the innersurrounding surface (61b) of the connecting receive mouth (61) at theinmost portion, and the axis of the ejection hole (85) is oriented insuch a direction as to spray the cleaning liquid (F) to the inmost endsurface (61a) and the sealing contact portion (89) of the receive mouth(61). On the midway of the connection between the first coupling (51)and the second coupling (52), a cleaning flow passage (C) is providedalong the whole length between the fitting surrounding surfaces of theconnecting receive mouth (61) and the connecting insert portion (161) asshown in FIG. 7(b).

The present invention functions as follows, as shown in FIGS. 7(a)through 7(c).

When the connection of the quick-acting coupling (26) is started, asshown in FIG. 7(a), the cleaning fluid (F) is adapted to be ejectedforward from the central portion of the connecting receive mouth (61)after flowing centripetally from the respective ejection holes (85) ofthe first coupling (51) and then blowing off the foreign substancesattached to the inmost end surface (61a) and the sealing contact portion(89) of the receive mouth (61).

When the engagement between the connecting receive mouth (61) and theconnecting insert portion (161) is started, as shown in FIG. 7(b), thecleaning fluid (F) flows centrifugally along the leading end surface(161a) of the connecting insert portion (161) to blow off the foreignsubstances therefrom and then flows forward through the cleaning flowpassage (C) to blow off the foreign substances attached to the innersurrounding surface (61b) of the receive mouth (61) and the outersurrounding surface (161b) of the insert portion (161). Then, as shownin FIG. 7(c), both the sealing contact portions (89), (189) are broughtinto contact with each other, and a first coupling side flow passage(60) and a second coupling side flow passage (160) are communicated toeach other under the sealed condition.

Since all the inmost end surface and the inner surrounding surface ofthe connecting receive mouth as well as the leading end surface and theouter surrounding surface of the connecting insert portion can becleaned in that way, the bitings of the foreign substances between boththe sealing contact portions can be prevented as well as the entering ofthe foreign substances into the first coupling side flow passage and thesecond coupling side flow passage can be also prevented.

Those and still other objects and advantages will be apparent from thefollowing description of the embodiment and its modifications of thepresent invention when taken in conjunction with the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 through 10 show embodiments of the present invention.

FIGS. 1 through 7 show a first embodiment thereof.

FIG. 1 is a diagram showing a whole system of a hydraulic clampapparatus;

FIG. 2 is a plan view showing a pressure oil supply and dischargecoupling means;

FIG. 3 is a front view showing the above coupling means;

FIG. 4 is a vertical sectional view showing the disconnected conditionof the quick-acting coupling;

FIG. 5 is a sectional view on V--V directed line in FIG. 4;

FIG. 6 is an enlarged view showing a principal part of the quick-actingcoupling under the connected condition thereof;

FIG. 7 is an explanatory view of the operations of the quick-actingcoupling, FIG. 7(a) is a view showing the disconnected conditionthereof, FIGS. 7(b) through 7(e) are views showing the connectiontransitive conditions thereof, and FIG. 7(f) is a view showing theconnected condition thereof;

FIG. 8 is a view showing a second embodiment corresponding to FIG. 4;

FIG. 9 is a vertical sectional view showing a socket (a first coupling)in a third embodiment; and

FIG. 10 is a vertical sectional view showing a plug (a second coupling)in a fourth embodiment.

FIGS. 11 and 12 show conventional embodiments respectively.

FIG. 11 is an explanatory view of the operations of a quick-actingcoupling of a first conventional embodiment, FIG. 11(a) is a viewshowing the connection starting condition thereof, FIGS. 11(b) and 11(c)are views showing the connection transitive conditions thereof, and FIG.11(d) is a view showing the connection completed condition thereof; and

FIG. 12 is an explanatory view of the operations of a quick-actingcoupling of a second conventional embodiment, FIG. 12(a) is a viewshowing the disconnected condition thereof, and FIG. 12(b) is a viewshowing the connected condition thereof.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Now, the embodiments of the present invention will be explained withreference to the drawings hereinafter.

First Embodiment

FIGS. 1 through 7 show the first embodiment thereof.

FIG. 1 shows a diagram of a whole system of such an apparatus as tosupply and discharge a pressure oil by means of a pressure oil supplyand discharge means 4 through a pressure oil supply and dischargecoupling means 3 relative to a hydraulic clamp 2 provided in a workpalette 1 for use in a machining center.

A work W and a plurality of hydraulic clamps 2 are mounted on the uppersurface of the work palette 1. The respective hydraulic clamps 2 areconstructed as follows.

When the work W is clamped, the work palette 1 and the pressure oilsupply and discharge means 4 are connected to each other by means of thecoupling means 3 so that the pressure oil is supplied to a clampactuating oil chamber 8 formed on the left side of a piston 7 within adouble-acting hydraulic cylinder 6 and the pressure oil is dischargedfrom an unclamp actuating oil chamber 9 formed on the right side of thepiston 7. Thereupon, the piston 7 and its piston rod 10 are advanced tothe right side, and the clamp arm 11 is shifted to its clamping positionindicated by the broken line in FIG. 1 through the piston rod 10. Whilethis clamped condition is maintained, the work palette 1 is disconnectedfrom the pressure oil supply and discharge means 4 and then the workpalette 1 is carried to the machining center (not illustrated) in orderto apply a machining to the work W. Incidentally, symbol 12 designates aclamped condition holding spring.

On the other hand, when the work W is unclamped, the work palette 1 andthe pressure oil supply and discharge means 4 are connected to eachother again by means of the coupling means 3 so that the pressure oil issupplied to the unclamp actuating oil chamber 9 and the pressure oil isdischarged from the clamp actuating oil chamber 8. Thereupon, the piston7 and the piston rod 10 are retreated to the left side against theclamped condition holding spring 12, and the clamp arm 11 is shifted toits unclamping position indicated by the solid line synchronously withthe retreating movement of the piston rod 10.

Incidentally, the work palette 1 is provided with a reserving cylinder13 for holding a clamping pressure and a balance cylinder 14.

Then, the pressure oil supply and discharge means 4 will be explained.It is provided with a booster pump 17 which is actuated by a pressurizedair supplied from a pneumatic source 16 so as to deliver a pressure oil.A clamp actuating changeover valve 20 is disposed in a clamp actuatingoil passage 18, and an unclamp actuating changeover valve 21 is disposedin an unclamp actuating oil passage 19. Both oil passages 18, 19 areextended from a delivery port of the booster pump 17. The hydraulicclamp 2 is actuated for the clamping through the coupling means 3 bychanging over the clamp actuating changeover valve 20 to its supplyposition and by changing over the unclamp actuating changeover valve 21to its discharge position. To the contrary, by changing over the unclampactuating changeover valve 21 to its supply position and by changingover the clamp actuating changeover valve 20 to its discharge position,the hydraulic clamp 2 is actuated for the unclamping through thecoupling means 3. The changeover manipulations for the respectivechangeover valves 20, 21 are carried out by means of pilot valves 22, 23respectively.

Then, the coupling means 3 will be explained. It is provided with twoquick disconnect couplings of the clamp actuating quick-acting coupling26 and an unclamp actuating quick-acting coupling 27, each of which 26,27 comprises the quick-acting coupling with check valves and non-spillvalves on opposite sides for use in liquid. The clamp actuating oilchamber 8 of the hydraulic clamp 2 and the clamp actuating oil passage18 of the pressure oil supply and discharge means 4 are connected ordisconnected by means of the clamp actuating quick-acting coupling 26.The unclamp actuating oil chamber 9 of the hydraulic clamp 2 and theunclamp actuating oil passage 19 of the pressure oil supply anddischarge means 4 are connected or disconnected by means of the unclampactuating quick-acting coupling 27. The construction and the operationof the coupling means 3 will be explained with reference to the systemdiagram of FIG. 1, a plan view of FIG. 2 and a front view of FIG. 3hereinafter.

A pneumatic cylinder 30 is fixedly secured to the upper surface of acoupling fixing pedestal P so that the work palette 1 can be carried toa predetermined position on the right side thereof and fixedly securedthereat. An advancement pneumatic actuation chamber 32 is formed on theleft side of a piston 31 within a pneumatic cylinder 30, and a retreatpneumatic actuation chamber 33 is formed on the right side thereof.Sockets 51, 51 as one side couplings (first couplings) composing therespective quick-acting couplings 26, 27 are fixed through a mountingbracket 35 to the leading end of a piston rod 34 projecting toward theright side from the piston 31. Corresponding thereto, plugs 52, 52 asthe other side couplings (second couplings) composing the respectivequick-acting couplings 26, 27 are fixed to the left portion of the workpalette 1. An advancement detecting limit switch 37 and a retreatdetecting limit switch 38 are fixed side by side on the pneumaticcylinder 30. These limit switches 37, 38 are adapted to be operablypushed respectively by means of an advancement detecting actuation rod39 and a retreat detecting actuation rod 40 projecting to the left sidefrom the bracket 35. A clamp pressure detecting limit switch 42 is fixedto the lateral side of the sockets 51, 51 corresponding to the pistonrod 13a of the reserving cylinder 13 fixed to the left portion of thework palette 1.

The above coupling means 3 operates as follows.

Under the unclamped disconnected condition shown in the drawing, when aclamp manipulation switch (not illustrated) is turned on, firstly apressurized air is supplied into the advancement pneumatic actuationchamber 32 through a pneumatic changeover valve 43 so that the piston 31and the piston rod 34 can be advanced to the right side. Synchronouslytherewith, the sockets 51, 51 are advanced to the right side so as to beconnected to the plugs 52, 52. Thereupon, the advancement detectingactuation rod 39 pushes and operates the advancement detecting limitswitch 37 so as to change over the clamp actuation changeover valve 20to its pressure supply position through the pilot valves 22, 23 as wellas to change over the unclamp actuation changeover valve 21 to itsdischarge position therethrough 22, 23 in order to extend the hydrauliccylinder 6 of the hydraulic clamp 2. When the hydraulic clamp 6 isextended sufficiently so that the work W can be clamped, the pressurewithin the pressure switch 45 disposed in the clamp actuation oilpassage 18 is increased to a predetermined clamp pressure and a pistonrod 13a of a reserving cylinder 13 is extended so as to push and operatea clamp pressure detecting limit switch 42.

Then, after the lapse of a predetermined time, the pneumatic changeovervalve 43 is changed over so that the pressurized air is supplied to theretreat pneumatic actuation chamber 33 and the sockets 51, 51 can beretreated to the left side through the piston 31 and the piston rod 34.Thereby, the hydraulic clamp 2 is disconnected under the clampedcondition. Simultaneously therewith, the retreat detecting limit switch38 is pushed and operated by means of the retreat detecting actuationrod 40 to detect the completion of the disconnection.

Incidentally, in the above operations, for the duration from theturning-on of the clamp actuation switch (not illustrated) to theoperation of the advancement detecting limit switch 37, the pressurizedair of the pneumatic source 16 is supplied from a pneumatic changeovervalve 48 for airblowing to the respective sockets 51, 51. Accordingly,since foreign substances attached to the leading end portions of therespective sockets 51, 51 and of the respective plugs 52, 52 are blownoff, the connection between the socket 51 and the plug 52 is carried outsmoothly.

To the contrary, in the case that the hydraulic clamp 2 is changed overfrom the above-mentioned clamped condition to the unclamped condition,when an unclamp actuation switch (not illustrated) is turned on, therespective sockets 51, 51 and the respective plugs 52, 52 are connectedto each other similarly as mentioned above. Thereupon, the advancementdetecting limit switch 37 is actuated so that the pressure oil can besupplied to the unclamp actuation oil chamber 9 of the hydraulic clamp 2through the unclamp actuation changeover valve 21 and the pressure oilwithin the clamp actuation oil chamber 8 can be discharged through theclamp actuation changeover valve 20. Accordingly, a pressure switch 46of the unclamp actuation oil passage 19 detects a pressure lowering andthe clamp pressure detecting limit switch 42 is released from itsactuation. After the lapse of a predetermined time from that time, thepressurized air is supplied to the retreat pneumatic actuation chamber33 through the pneumatic changeover valve 43 so that the sockets 51, 51can be retreated to the left side. Thereby the hydraulic clamp 2 isdisconnected under the unclamped condition. Simultaneously therewith,the retreat detecting actuation rod 40 pushes and actuates the retreatdetecting limit switch 38 so as to detect the completion of thedisconnected condition.

In the coupling means 3 having the above-mentioned construction, twoquick-acting couplings 26, 27 are constructed similarly. The concreteconstruction thereof will be explained with reference to FIGS. 4 through7 and FIG. 1.

Firstly, the socket 51 will be explained with reference to FIG. 4.Within the body 53 as the coupling body there are provided a connectingreceive mouth 61, a socket side flow passage 60 as a first coupling sideflow passage and an oil supply and discharge port 62 in order from thebutt connection side (on the right side in FIG. 4 ) JA to the pull-offdisconnection side (on the left side therein ) UA. Within the socketside flow passage 60 there are provided a check valve body 54, anon-spill valve body 55, a non-spill valve casing 56, a check valvespring 57, a non-spill valve casing spring 58 and a rod 59.

That is, the receive mouth 61 is formed by concaving the central portionof the socket body 53 on the butt connection side JA, and the socketside flow passage 60 is opened in the inmost end surface 61a of thereceive mouth 61. Within the socket side flow passage 60 there areprovided a non-spill valve casing chamber 63, a rod chamber 64, a firstannular filter chamber 65 formed outside the rod chamber 64, a checkvalve chamber 66 and a second filter chamber 67. A cylindrical filter 68is accommodated within the first filter chamber 65, and a disk-likefilter 69 is accommodated within the second filter chamber 67. The checkvalve body 54 and the check valve spring 57 are accommodated within thecheck valve chamber 66. Further, the non-spill valve casing 56 isaccommodated within the non-spill valve casing chamber 63.

A cylindrical non-spill valve port surface 71 is formed in the leadingend portion of the casing bore 56a of the nonspill valve casing 56, andthe non-spill valve body 55 is fitted slidably inside the non-spillvalve port surface 71. The inside of the non-spill valve port surface 71is communicated with the check valve chamber 66 through the casing bore56a of the non-spill valve casing 56, the rod chamber 64 and thecylindrical filter 68.

Further, the non-spill valve body 55 is connected to the check valvebody 54 through the rod 59. The check valve body 54 is urged toward thebutt connection side JA on the right side by means of the check valvespring 57 within the check valve chamber 66 so as to be butted on thecheck valve seat 72 of the check valve chamber 66 for the valve closing.The rod 59 is separated into two portions of a front rod 73 and a backrod 74. The non-spill valve body 55 is integrated with the leading endof the front rod 73. On one hand, these rods 73, 74 transmit themovement of the non-spill valve body 55 toward the pull-offdisconnection side (the left side ) UA by an external force to the checkvalve body 54 so as to shift the check valve body 54 to its valveopening position. On the other hand, the front rod 73 limits themovement of the non-spill valve body 55 toward the butt connection side(the right side ) JA by means of its engaging portion 73a. Incidentally,though the rod 59 is divided into two pieces in order to facilitate theassembly of the quick-acting coupling 26, it may be also possible tolimit the movement of the non-spill valve body 55 toward the buttconnection side JA by means of the check valve seat 72 after therespective component parts of those non-spill valve body 55, front rod73, back rod 74 and check valve body 54 are integrated as one piece.

The non-spill valve casing 56 is urged toward the butt connection sideJA on the right side by means of the nonspill valve casing spring 58within the non-spill valve casing chamber 63 so that the non-spill valveport surface 71 can be closed by means of the non-spill valve body 55.Under the valve closed condition of the non-spill valve body 55, thefront side space and the back side space thereof are communicated toeach other through a fitting gap (a communication passage ) 75 having asmall cross-sectional area (refer to FIG. 6 ). However, since thefitting gap 75 is very small, the non-spill valve casing chamber 63 isblocked liquidly by means of surface tension of the working oil.

Further, a butt connection alignment device 77 is provided in the socket51.

That is, an eccentricity allowing casing 78 is fitted in the socket body53 on the butt connection side JA so as to be radially movable under theliquid-tight condition. The eccentricity allowing casing 78 comprises aconnecting mouthpiece casing 79 having the connecting receive mouth 61and a guide cylinder 80 fitted therein. The guide cylinder 80 iscentrally held by means of a plurality of positioning springs 81. Thenon-spill valve casing 56 is accommodated within the bore of the guidecylinder 80 so as to be movable in a fore and rear direction under theliquid-tight condition. A declination allowing ring 82 is externallyfitted to the leading end portion of the non-spill valve casing 56 so asto be swingable declinationally. A sealing means 84 composed of anO-ring is fitted between the declination allowing ring 82 and thenon-spill valve casing 56. A sealing contact portion 89 is formed in theleading end surface of the sealing means 84. Under the butted connectedcondition (refer to FIG. 6 ), the valve casing pushing portion 156provided at the leading end of the plug 52 is adapted to push thenon-spill valve casing 56 toward the pull-off disconnection side UA onthe left side through the declination allowing ring 82.

Further, the inner surrounding surface 61b of the connecting receivemouth 61 is provided at a plurality of locations in its circumferentialdirection with ejection holes 85 for ejecting a pressurized air F as acleaning fluid. That is, these ejection holes 85 are formed in theleading end surface of the declination allowing ring 82 disposed at theinmost portion of the inner surrounding surface 61b of the receive mouth61. The axes of the respective ejection holes 85 are oriented in such adirection as to spray the pressurized air F onto the inmost end surface61a of the receive mouth 61 and the sealing contact portion 89. Therespective ejection holes 85 are communicated with an air supply port 87for an air blowing through a plurality of communication holes 86 formedin the connecting mouthpiece casing 79. The positioning spring 81 isaccommodated within each of the communication holes 86.

Then, the plug 52 will be explained hereinafter.

The plug 52 has a plug body 153 as a coupling body provided with aconnecting insert portion 161, a plug side flow passage 160 as a secondcoupling side flow passage and an oil supply and discharge port 162arranged from the butt connection side (the left side in the drawings )JB to the pull-off disconnection side (the right side therein ) UBthereof. Within the plug side flow passage 160 there are provided acheck valve body 154, a non-spill valve body 155, a check valve spring157, a non-spill valve spring 158 and a rod 159.

That is, the plug side flow passage 160 is opened in the leading endsurface 161a of the connecting insert portion 161, and annular sealingcontact portion 189 is formed therein 161a corresponding to the sealingcontact portion 89 of the socket 51. As shown in FIG. 6, both thesealing contact portions 89, 189 are kept in contact with each other soas to seal a space between both the fitting surfaces of the connectingreceive mouth 61 and the connecting insert portion 161 under theconnected condition of both the socket 51 and the plug 52.

Within the plug side flow passage 160 there are provided the non-spillvalve chamber 163, the rod chamber 164, an annular first filter chamber165, a check valve chamber 166 and a second filter chamber 167. Acylindrical filter 168 is accommodated within the first filter chamber165, and the non-spill valve chamber 163 is communicated with the checkvalve chamber 166 through the cylindrical filter 168. A disk-like filter169 is accommodated within the second filter chamber 167.

The check valve body 154 and the check valve spring 157 are accommodatedwithin the check valve chamber 166, and the non-spill valve body 155 isaccommodated within the non-spill valve chamber 163. The cylindricalnon-spill valve port surface 171 is formed in the leading end portion ofthe non-spill valve chamber 163, and the non-spill valve body 155 isinternally fitted slidably to the non-spill valve port surface 171. Therod 159 is interposed between the non-spill valve body 155 and the checkvalve body 154 within the rod chamber 164.

The check valve body 154 is urged toward the butt connection side JB onthe left side by means of the check valve spring 157 within the checkvalve chamber 166 so as to be butted on the check valve seat 172 of thecheck valve chamber 166 for closing the valve. The rod 159 transmits themovement of the non-spill valve body 155 toward the pull-offdisconnection side (the right side ) UB by an external force to thecheck valve body 154 so as to shift the check valve body 154 to itsvalve opening position. In this case, instead of the rod 159 formedseparately from the check valve body 154, the rod may be formedintegratedly therewith 154.

The non-spill valve body 155, on one hand, is urged to the buttconnection side JB on the left side by means of the non-spill valvespring 158 within the non-spill valve chamber 163 so as to close thenon-spill valve port surface 171 of the non-spill valve chamber 163 and,on the other hand, is urged to the pull-off disconnection side UB on theright side by an external force so as to open the non-spill valve portsurface 171. Under the valve closed condition of the non-spill valvebody 155, the front side space and the back side space thereof arecommunicated to each other through a fitting gap (a communicationpassage ) 175 having a small cross-sectional area. Since the fitting gap175 is very small, the non-spill valve chamber 163 is liquidly blockedby means of surface tension of the working oil.

The quick-acting coupling 26 having the above-mentioned constructionoperates as follows, as shown in FIG. 7 when the socket 51 and the plug52 thereof are butted for the connection.

When the connecting manipulation is started under the disconnectedcondition as shown in FIG. 7(a), the advancement of the socket 51 isstarted and simultaneously the sealing contact portion 89 provided inthe leading end surface of the sealing means 84 of the socket 51 iscleaned by the blow of the pressurized air (the cleaning fluid ) F.

As shown in FIG. 7(b), a cleaning flow passage C for the pressurized airF is formed along the whole length between the fitting surroundingsurfaces of the connecting receive mouth 61 and the connecting insertportion 161 under the midway condition of the connection between thesocket 51 and the plug 52. Thereby, the pressurized air F ejected fromthe ejection holes 85 is adapted to be sprayed to the leading endsurface 161a and the outer surrounding surface 161b of the connectinginsert portion 161. Subsequently, as shown in FIG. 7(c), a space betweenboth the fitting surfaces of the receive mouth 61 and the insert portion161 is sealed by means of the sealing means 84.

Then, as shown in FIG. 7(d), the non-spill valve casing 56 is pushed tothe pull-off disconnection side UA on the left side by means of thevalve casing pushing portion 156 of the plug 52. Thereby, both the rods59, 159 are butted to each other, and the rod 159 compresses thenonspill valve spring 158 so as to be butted on the check valve body154.

Further, when both the non-spill valve bodies 55, 155 are butted to eachother to be pushed toward the pull-off disconnection sides UA, UB, thefollowing operations are carried out.

Firstly, as shown in FIG. 7(e), the check valve body 54 of the socket 51compresses the check valve spring 57 so as to open the valve. Then, whenthe check valve body 154 of the plug 52 starts to compress the checkvalve spring 157 so as to open the valve, simultaneously both thenon-spill valve bodies 55, 155 start to open the valves.

As shown in FIG. 7(f), all the valve bodies 54, 55, 154, 155 are shiftedto their fully opened positions so as to complete the connection whilethe non-spill valve casing 56 is received within the coupling body 53.

In the case that the axes of both the couplings 51, 52 inclinerelatively at the time of connecting manipulation of the aforementionedquick-acting coupling 26, the alignment device 77 shown in FIG. 4functions as follows so that the connecting manipulation can be carriedout smoothly.

That is, when the connecting manipulation is started, firstly the valvecasing pushing portion 156 of the plug 52 swings the declinationallowing ring 82 of the socket 51 about the non-spill valve casing 56 sothat the axes of the plug 52 and of the declination allowing ring 82coincide with each other. Then, the declination allowing ring 82retreats the non-spill valve casing 56 toward the pull-off disconnectionside UA within the eccentricity allowing casing 78 while allowing theeccentricity allowing casing 78 to move eccentrically through thenon-spill valve casing 56. Thereby, the connecting manipulation can becarried out smoothly without any entanglement between the valve casingpushing portion 156 of the plug 52 and the socket body 53 of the socket51.

To the contrary, when the socket 51 and the plug 52 are pulled off so asto be disconnected from the connected condition shown in FIG. 7(f), thefollowing operations are carried out as shown in FIG. 7.

When the socket 51 is retreated to the pull-off disconnection side UA onthe left side, the check valve spring 157 of the plug 52 is extended sothat firstly, as shown in FIG. 7(e), the non-spill valve body 155 can beshifted to its valve closing position and the check valve body 154 canbe also shifted to its valve closing position. Then, as shown in FIG.7(d), the check valve spring 57 of the socket 51 is extended so that thecheck valve body 54 can be shifted to its valve closing position. Whilethe non-spill valve casing 56 of the socket 51, the non-spill valve body155 of the plug 52 and both the check valve bodies 54, 154 are pushed bymeans of the respective springs 57, 58, 157, 158 as shown in FIG. 7(c),the socket 51 and the plug 52 are disconnected as shown in FIG. 7(b).

In this case, while the socket 51 and the plug 52 are changed over fromthe connected condition wherein they are butted and connected to eachother to the disconnected condition wherein they are disconnected bypulling off, the total operation lift L (refer to FIG. 7(c) and FIG.7(f) ) of the non-spill valve casing 56 brought about by the nonspillvalve spring 58 toward the butt connection side JA is set larger by thesucking back lift N (refer to FIG. 7(d) ) than the all-valve closingminimum lift M (refer to FIG. 7(d) ) of the non-spill valve casing 56required in minimum for the completion of the closing shifts of all therespective check valve bodies 54, 154 and the respective non-spill valvebodies 55, 155. Therefore, for the duration from the condition shown inFIG. 7(d) to the condition shown in FIG. 7(c), the pressures within thecasing bore 56a of the non-spill valve casing 56 and within thenon-spill valve chamber 163 are lowered to a negative pressure by theadvancement of the non-spill valve casing 56 toward the butt connectionside JA. Thereby, when changing over from the condition shown in FIG.7(c) to the condition shown in FIG. 7(b), the working oil pooled in theinside circumferential space of the sealing means 84 is sucked back intothe non-spill valve casing chamber 63 and non-spill valve chamber 163 soas to prevent the spill-out of the working oil perfectly.

Since the cylindrical filters 68, 168 having large filtering capacitiesare mounted, as shown in FIG. 4, between the non-spill valve casingchamber 63 and the check valve chamber 66 and between the non-spillvalve chamber 163 and the check valve chamber 166 where are provided aspace communicating to the outside at the time of pulling off for thedisconnection of both the aforementioned couplings 51, 52, thefilter-changing frequency becomes less so as to save labor for themaintenance differently from the disk-like filter of the secondconventional embodiment (refer to FIG. 12 ).

By the way, though the respective casing bores of the non-spill valveport surfaces 71, 171 are circular in the above-mentioned embodiment,they may be polygonal so as to receive the non-spill valve bodies 55,155 having corresponding polygonal cross-sectional shapes.

Further, the respective communication passage for communicating thefront spaces and the back spaces of the non-spill valve bodies 55, 155to each other under the valve closed conditions thereof may be formed bysmall-diameter holes passing through the non-spill valve bodies 55, 155instead of the fitting gaps 75, 175.

Further, though the plug 52 is provided with the check valve spring 157and the non-spill valve spring 158 separately, the non-spill valvespring may be omitted by substituting the check valve spring for thenon-spill valve spring.

Further more, though the aforementioned quick-acting coupling 26 employsthe pneumatic cylinder 30 which serves to exert the external force forconnecting and disconnecting the coupling 26, a man power may be usedfor such a connecting and disconnecting actuation. Instead of theworking oil, other liquids may be used for the coupling.

FIGS. 8 through 10 show other embodiments respectively. The differentconstructions from the above-mentioned first embodiment will beexplained. The component parts having the same functions as the ones inthe first embodiment are designated by the same symbols in principle.

Second Embodiment

FIG. 8 shows a second embodiment.

Respective check valve bodies 254, 354 of the socket 51 as the firstcoupling and of the plug 52 as the second coupling are formed like amushroom. Guide portions 291, 391 of the respective check valve bodies254, 354 are fitted in the socket body 53 and in the plug body 153respectively so as to be guided thereby. The respective guide portions291, 391 are provided at their circumferential surfaces with oil supplygrooves 292, 392 concaved therein. Since the check valve bodies 254, 354are formed like a mushroom, wide flow passages can be provided in theouter circumferential portions of the check valve bodies 254, 354 withincheck valve chambers 266, 366. Therefore, flow resistance in thequick-acting coupling becomes smaller.

In the plug 52, the left end surface of a non-spill valve body 355 isprojected outside the left end surface of valve casing pushing portion356. Therefore, at the time of disconnecting manipulation of thequick-acting coupling, since an advancement stroke of the non-spillvalve body 355 toward the left side with respect to the plug body 153becomes larger, the spill preventive function is further improved. Whenthe blow for cleaning is carried out by a pressurized fluid at the timeof connecting manipulation of the quick-acting coupling, the leading endsurface of the non-spill valve body 355 can be cleaned sufficiently bythe blow because the non-spill valve body 355 is projected outside.

Further, in the plug 52, the left side outer circumferential surface ofa rod 359 is fitted slidably in the connecting insert portion 361 of theplug body 153 so as to be guided therein. The rod 359 is provided at itsfitting outer circumferential surface with a plurality of communicationgrooves 394 concaved therein so as to extend in the axial direction ofthe rod 359. Thereby, the rod 359 is guided smoothly and the non-spillvalve body 355 can be prevented from being entangled.

Incidentally, the left shoulder portion 359a of the rod 359 is broughtinto contact with the valve casing pushing portion 356, and the oppositeleft and right sides of the contact portions are communicated to eachother through concave portions of the rough surfaces by making thefinishings of the respective contact portions rough.

Third Embodiment

FIG. 9 shows a third embodiment and is a vertical sectional view of thesocket 51.

In this case, a rod 459 is formed as one piece. Therefore, since anaccumulation of size errors can be removed from the longitudinal size ofthe rod 459 differently from the assembly rod comprising a plurality ofrods arranged longitudinally, its dimensional accuracy can be enhancedreadily. Further, since the rod 459 is manufactured as one piece, itsmanufacturing cost can be lowered.

A cylindrical filter 469 is mounted in an annular filter chamber 467formed between a check valve chamber 466 and a liquid supply anddischarge port 462. Accordingly, since the filtering capacity of thefilter 467 can be enlarged, the maintenance for the socket 51 can becarried out readily.

Fourth Embodiment

FIG. 10 shows a fourth embodiment and is a vertical sectional view. Thisembodiment is obtained by modifying the plug shown in FIG. 8 as follows.

That is, a cylindrical filter 569 is mounted in an annular filterchamber 567 formed between a check valve chamber 566 and a liquid supplyand discharge port 562. Accordingly, the filtering capacity of thefilter 569 can be enlarged and the maintenance for the plug 52 can bemade easy.

Incidentally, though the first coupling comprises the socket and thesecond coupling comprises the plug, the first coupling may comprise aplug and the second coupling may comprise a socket for providing a spillpreventive function for the quick-acting coupling.

What is claimed is:
 1. A quick-acting coupling with a fluid blow typecleaning device, comprising:a socket-like first coupling (51) and aplug-like second coupling (52), a coupling body (153) of said secondcoupling (52) being provided at its leading end portion with aconnecting insert portion (161), said connecting insert portion (161)having a leading end surface (161a) and an outer surrounding surface(161b), a second coupling side flow passage (160) being opened in saidleading end surface (161a), and an annular sealing contact portion (189)being formed in said leading end surface (161a) along the opening edgeof said flow passage (160), a coupling body (53) of said first coupling(51) being provided at its leading end portion with a connecting receivemouth (61) concaved therein, said connecting receive mouth (61) havingan inmost end surface (61a) and an inner surrounding surface (61b), afirst coupling side flow passage (60) being opened in the inmost endsurface (61a), and an annular sealing contact portion (89) being formedin said inmost end surface (61a) along the opening edge of said flowpassage (60), the inner surrounding surface (61b) of said connectingreceive mouth (61) being provided at least at a plurality of locationsin its circumferential direction with ejection holes (85) for ejecting acleaning fluid (F), said ejection holes (85) being opened in the innersurrounding surface (61b) of the connecting receive mouth (61) at itsinmost portion, and the axes of said ejection holes (85) being orientedin such a direction as to spray the cleaning fluid (F) onto the inmostend surface (61a) of the connecting receive mouth (61) and the sealingcontact portion (89), under the midway condition of the connectionbetween said first coupling (51) and said second coupling (52), acleaning flow passage (C) for the cleaning fluid (F) being formed alongthe whole length between the fitting surround surfaces of the connectingreceive mouth (61) and the connecting insert portion (161), and saidcleaning fluid (F) ejected from the ejection holes (85) being adapted tobe sprayed onto the leading end surface (161a) and the outer surroundingsurface (161b) of the connecting insert portion (161) for the cleaning,and under the connected condition between the first coupling (51) andthe second coupling (52), both the sealing contact portions (89) (189)being brought into contact with each other so as to seal between thefitting surfaces of the connecting receive mouth (61) and the connectinginsert portion (161).
 2. A quick-acting coupling as defined in claim 1,whereinthe coupling body (53) of said first coupling (51) is provided atits leading end portion with a butt connection alignment device (77),said alignment device (77) comprises an eccentricity allowing casing(78), an inner casing (56) and a declination allowing ring (82), saideccentricity allowing casing (78) is disposed in the coupling body (53)hermetically and movably in an eccentric direction with respect to thebutting direction thereof, said connecting receive mouth (61) is formedin the leading end portion of the eccentricity allowing casing (78),said inner casing (56) is accommodated within the end portion of theeccentricity allowing casing (78) hermetically and movably in thebutting direction thereof, and said first coupling side flow passage(60) is provided within the inner casing (56), said declination allowingring (82) is fitted externally onto the leading end portion of the innercasing (56) so as to be declinationally swingable, and said sealingcontact portion (89) is provided in the leading end surface of the innercasing (56), and under the connection manipulating condition for buttingand connecting the first coupling (51) and the second coupling (52) toeach other, the sealing contact portion (189) of said second coupling(52) is adapted to push the inner casing (56) toward the inmost sidethrough the sealing contact portion (89) and the declination allowingring (82) of said first coupling (51).